Well don't worry, that's about to change. EW reveals that in the December 11th episode, Oliver will indeed trade up the makeup he's been wearing for an actual mask.

Oliver Queen (Stephen Amell) gets his mask on in Arrow.

Arrow executive producer Andrew Kreisberg tells EW, ”Conceptually, it was something we wanted to do because Oliver himself is evolving as the Arrow -- from vigilante to hero, sort of from Arrow to Green Arrow -- and we wanted to see that progression in his costume as well. As Oliver is embracing being a hero, being a hero means stepping out of the dark and being more of a symbol, so he has to take steps to conceal his identity more.”

The mask's introduction will be a notable story point, with Kreisberg telling EW, “He doesn’t just put on a mask. It’s actually a big plot point in an episode, and there really is a story behind, not only the need for the mask but also who provides him with it. It’s going to be a little bit of a surprise, and once they see how the mask comes into creation, I think people will be really excited about it.”

You can read more about the mask at EW, including how they avoided using some "Joel Schumacher-esque" design choices.